Beneath Thunderspire Mountain lies a sprawling network of mazes, tombs, and caverns collectively known as the Labyrinth. In recent years, this vast labyrinth has become a living dungeon where trade between the surface and subterranean worlds is possible. However, beyond the well-lit halls where prospectors, merchants, and traders convene lies a darker world where adventurers battle monsters and fiendish beings perform secret rituals for their dark masters....

H2 Thunderspire Labyrinth is a D&D adventure designed for heroic-tier characters of levels 4–6. It can be played as a standalone adventure or as the second part of a three-part series. This product includes an adventure booklet for the Dungeon Master, a campaign guide with player handouts, and a full-color poster map, all contained in a handy folder.

H2 Thunderspire Labyrinth is the second adventure in a three-part series that began with H1 Keep on the Shadowfell and concludes with H3 Pyramid of Shadows. It can also be played as a stand-alone adventure.

Pursuing a gang of slavers, the characters come to the vast Labyrinth - a long-ruined minotaur city beneath the mountain known as Thunderspire. Here, folk from the surface and the Underdark meet in lantern-lit halls under the protection of the mysterious Mages of Saruun. Rescuing the slavers' hapless captives only leads to deeper and darker threats, as vicious demon-tainted gnolls secretly plot with renegade mages to seize Thunderspire for their own.